<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>getElementsByTagName获取checkbox进行全选</title>
		<style type="text/css">
			#myTable{ width: 900px; margin: 0px auto; background-color: #008000;}
			#myTable td,#myTable th{ background-color: white;}
			#myDiv{width: 900px; margin: 0px auto; height: 30px; line-height: 30px; 
			text-align: center;}
		</style>
		<!-- <script>======代码======</script> -->
	</head>
	<body>
		<table cellspacing="1" id="myTable">
			<tr>
					<th width="200">
					<input type="checkbox" id="selAll" onchange="all()" />全选
					<input type="checkbox" id="selAll" onchange="lla()" />反选
					</th>
				<th width="200">姓名</th>
				<th width="200">性别</th>
				<th width="200">专业</th>
				<th width="200">爱好</th>
			</tr>
		<div id="div">
			<tr>
				<td><input type="checkbox"/></td>
				<td>刘备</td>
				<td>男</td>
				<td>软件开发</td>
				<td>抽烟</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>关羽</td>
				<td>男</td>
				<td>国际贸易</td>
				<td>喝酒</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>张飞</td>
				<td>男</td>
				<td>园林设计</td>
				<td>烫头发</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>赵云</td>
				<td>男</td>
				<td>平面设计</td>
				<td>抽烟</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>黄忠</td>
				<td>男</td>
				<td>影视制作</td>
				<td>玩游戏</td>
			</tr>
			<tr>
				<td><input type="checkbox"/></td>
				<td>小乔</td>
				<td>女</td>
				<td>高级护理</td>
				<td>唱歌</td>
			</tr>
		</div>
			
		</table>

		<script>
			var table=document.getElementById('myTable');
			var sel=document.getElementById('selAll');
			var div=document.getElementById('div')
			var input=div.getElementsByTagName('input');

			var len=input.length;
			function all() {
				if (this.checked){
					for (let i = 0; i < len; i++) {
						input[i].checked=false;
				}
				}else{
					for (let i = 0; i < len; i++) {
						input[i].checked=true;
					}
				}
			}
				
			
		</script>
	</body>
</html>